The Junior Finance Minister Brian Hayes has said when key jobs come up in the public service they need to go to people who are out of work.
It has emerged that the Department of Agriculture has re-hired 59 veterinary inspectors, after they retired.
Fianna Fáil's Billy Kelleher said the same is true for a number of other departments.
It is understood the chief medical officer for the Department of Social Protection is now back in his job on a salary of more than €100,000 a year, after his retirement earlier this year.
Several government departments say re-hired staff have been subject to the "abatement" principle, where the sum of their pension and salary does not exceed a full-time salary for the same job.
Mr Hayes has said the Government needs to keep a close eye on the matter, but insists the figures are not that high.
He said: "The numbers are not huge and in the great majority of cases they are to do with specialist positions across the public service.
"I understand they are for a short period of time, but obviously the key challenge where additional jobs come up in the public service is that they should go to people who are out of work and we should keep a close eye on this, and we are."